#include <iostream>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <string>
#include <map>
#define INIT 400000
using namespace std;

struct eight
{
bool b;
int sum;
eight():b(false),sum(0)
{

}
};
int ans=INIT;
map<string,eight> judge;
queue<string> q;

void BFS(const string& str)
{
string t;
judge[str].b=true;
q.push(str);
while(q.empty()==false)
{
t=q.front();
q.pop();
if(t=="123804765")
ans=min(ans,judge[t].sum);
else if(judge[t].sum<ans)
{
int loc=t.find('0');
int x=loc/3;
int y=loc%3;
int step=judge[t].sum;
if(x-1>=0)
{
swap(t[loc],t[loc-3]);
if(judge[t].b==false)
{
judge[t].b=true;
judge[t].sum=step+1;
q.push(t);
}
swap(t[loc],t[loc-3]);
}
if(y-1>=0)
{
swap(t[loc],t[loc-1]);
if(judge[t].b==false)
{
judge[t].b=true;
judge[t].sum=step+1;
q.push(t);
}
swap(t[loc],t[loc-1]);
}
if(y+1<=2)
{
swap(t[loc],t[loc+1]);
if(judge[t].b==false)
{
judge[t].b=true;
judge[t].sum=step+1;
q.push(t);
}
swap(t[loc],t[loc+1]);
}
if(x+1<=2)
{
swap(t[loc],t[loc+3]);
if(judge[t].b==false)
{
judge[t].b=true;
judge[t].sum=step+1;
q.push(t);
}
swap(t[loc],t[loc+3]);
}
}
}
}

int main()
{
string str;
cin>>str;
if(str=="123804765")
cout<<0<<endl;
else
BFS(str);
if(ans==INIT)
cout<<-1<<endl;
else
cout<<ans<<endl;
return 0;
}
//我尽力了！！！！

#include <iostream>
#include <queue>
#include <cmath>
#include <cstring>
using namespace std;

char target[10] = "123804765";
int target_hash;
const int pos[][2]={{1,1},{0,0},{0,1},{0,2},{1,2},{2,2},{2,1},{2,0},{1,0}};
bool vis[500000];
int hashs[10];

struct Node {
int f,g,h;
char c[10];
friend bool operator < (const Node &a,const Node &b){
if(a.f == b.f) return a.g < b.g;
return a.f > b.f;
}

};

/*
void print(const Node &n){
cout<<"Node: "<<n.f<<" = "<<n.g<<" + "<<n.h<<endl;
for(int i=0,j;i<3;i++){
for(j=0;j<3;j++)
cout<<n.c[i*3+j]<<" ";

cout<<endl;
}
cout<<endl;
}
*/

int unmatch(const char * c){
int cnt = 0;
for(int i=0,j;i<3;i++){
for(j=0;j<3;j++){
int p = c[i*3+j] - '0';
if(p == 0) continue;
//if(abs(pos[p][0] - i) || abs(pos[p][1] - j))
//cnt+=1;
cnt+=abs(pos[p][0] - i) + abs(pos[p][1] - j);
}
}
return cnt;
}

int cantor(const char * c){
int cnt=0,tmp;
for(int i=0,k;i<9;i++){
tmp = 0;
for(k=i-1;k>=0;k--){
if(c[k]>c[i]) tmp++;
}
cnt += hashs[i] * tmp;
}
return cnt;
}

bool up(char * c){
int p0=-1;
while(1){
if(c[++p0] == '0') break;
}
if(p0>5) return false;
c[p0] = c[p0+3];
c[p0+3] = '0';
return true;
}

bool down(char * c){
int p0=-1;
while(1){
if(c[++p0] == '0') break;
}
if(p0<3) return false;
c[p0] = c[p0-3];
c[p0-3] = '0';
return true;
}

bool left(char * c){
int p0=-1;
while(1){
if(c[++p0] == '0') break;
}
if(p0%3 == 2) return false;
c[p0] = c[p0+1];
c[p0+1] = '0';
return true;
}

bool right(char * c){
int p0=-1;
while(1){
if(c[++p0] == '0') break;
}
if(p0%3 == 0) return false;
c[p0] = c[p0-1];
c[p0-1] = '0';
return true;
}

int search(Node n){
target_hash = cantor(target);
if(cantor(n.c) == target_hash) return 0;
vis[cantor(n.c)]=true;
memset(vis,0,sizeof(vis));
priority_queue<Node> que;
que.push(n);
while(!que.empty()){
Node curr = que.top();
que.pop();

Node set[4];
set[0]=set[1]=set[2]=set[3]=curr;
up(set[0].c);left(set[1].c);down(set[2].c);right(set[3].c);
for(int i=0;i<4;i++){
set[i].g=curr.g+1;
set[i].h=unmatch(set[i].c);
set[i].f=set[i].g+set[i].h;
int t = cantor(set[i].c);
//cout<<i<<" "<<t<<":"<<endl;
//print(set[i]);
if(t == target_hash) return set[i].g;
if(!vis[t]){
vis[t] = true;
que.push(set[i]);
//cout<<"pushed"<<endl<<endl;
}
}
}
}

int main(){

hashs[0]=1;
for(int i=1;i<11;i++){
hashs[i] = hashs[i-1] * i;
}
Node start;
cin>>start.c;
//strcpy(start.c,"203184765");
start.g=0;
start.h=unmatch(start.c);
start.f=start.g+start.h;
//print(start);
cout<<search(start);
return 0;
}

#include <iostream>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <string>
#include <map>
#define INIT 400000
using namespace std;

struct eight
{
bool b;
int sum;
eight():b(false),sum(0)
{

}
};
int ans=INIT;
map<string,eight> judge;
queue<string> q;

void BFS(const string& str)
{
string t;
judge[str].b=true;
q.push(str);
while(q.empty()==false)
{
t=q.front();
q.pop();
if(t=="123804765")
ans=min(ans,judge[t].sum);
else if(judge[t].sum<ans)
{
int loc=t.find('0');
int x=loc/3;
int y=loc%3;
int step=judge[t].sum;
if(x-1>=0)
{
swap(t[loc],t[loc-3]);
if(judge[t].b==false)
{
judge[t].b=true;
judge[t].sum=step+1;
q.push(t);
}
swap(t[loc],t[loc-3]);
}
if(y-1>=0)
{
swap(t[loc],t[loc-1]);
if(judge[t].b==false)
{
judge[t].b=true;
judge[t].sum=step+1;
q.push(t);
}
swap(t[loc],t[loc-1]);
}
if(y+1<=2)
{
swap(t[loc],t[loc+1]);
if(judge[t].b==false)
{
judge[t].b=true;
judge[t].sum=step+1;
q.push(t);
}
swap(t[loc],t[loc+1]);
}
if(x+1<=2)
{
swap(t[loc],t[loc+3]);
if(judge[t].b==false)
{
judge[t].b=true;
judge[t].sum=step+1;
q.push(t);
}
swap(t[loc],t[loc+3]);
}
}
}
}

int main()
{
string str;
cin>>str;
if(str=="123804765")
cout<<0<<endl;
else
BFS(str);
if(ans==INIT)
cout<<-1<<endl;
else
cout<<ans<<endl;
return 0;
}///////////////////////////对(666)